1. Field of the Invention
Efficient dynamo-based production of electrical power in environmental energy harvesting and other applications in which the dynamo rotor is driven at low and variable revolutions per minute. Specific applications include, by way of example, powering systems aboard unmanned maritime platforms and harvesting wind power generation.
2. Description of the Related Art
Extraction of useful energy from locally available environmental sources is becoming vitally important to a wide range of applications, and immediately so for remote sensing and communications devices for military and civilian uses. A common element in all devices that harvest environmental energy from kinetic sources such as moving wind or water is the electrical dynamo, which must be capable of operating without an external source of current and therefore typically utilizes permanent magnets. Numerous electrical dynamo designs exist and are patented. In particular, these designs include vertical and horizontal axis wind turbines and kinetic power pendulum-type devices which respond to X-Y forces (with respect to the pendulum's rotational axis).
One of the problems associated with high-efficiency, radial flux, permanent magnet alternators is cost of fabrication when the rotor size exceeds 5 or 6 inches. The cost of rare earth magnets dominates the cost equation today, so any reduction in the cost of other components presents opportunities to reduce overall cost.
Accordingly, there is a perpetual need in the alternator (dynamo) art for improved technical designs which balance intended application, size, costs and other factors to meet efficiency demands.